Non woven polyster grafts modified with collagen and mucopolysaccharide (2-2.5mmφ) were prepared and their blood compatibility was examined in viva and in vitro. Collagen was crosslinked with dialdehyde starch. The thin and smooth layer of pseudointima on the luminal surface in short-term use within 40hrs. has been obselved. Graft inner surface characteristics are probably more important than porosity in determing eventual patency. However, the problems associated with pannus formation, especially at the anastomotic site still remain for this surface modified small bore vascular prosthesis in long-term use over 2 months.

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To assess elastic properties of synthetic vascular prostheses, compliance of arterial grafts was measured in vitro and in vivo examination using ultrasonic displacement measuring system combined with B mode imaging. Compliance derived from systolic-diastolic pressure gradient and diameter change of grafts obtained from displacement meter. Biograft was more compliant than ve lour knitted Dacron, auto saphenous vein and EPTFE. As compared compliance of human arteries to that of various arterial grafts, Biograft showed simillar elasticity of human femoral artery.

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A new small caliber prosthesis available for aorto-coronary bypass grafting, aorto-pulmonary, blood access and others was developed by means of segmented polyurethane. It was evaluated in the term of porosity, compliance, and stress-strain curve. Moreover, the patterns of stress-strain curve were simulated into those of native vessels, by the technique of double layers. Twelve kinds of the prostheses were evaluated using the site of femoral arteries in mongrel dogs, and one of them was found to be 80% patent within 1 year. The patency of double layered prostheses was 0%, but the reason why they closed seemed to be too stiff and due to anti-thrombogenicity of polymer structure itself.

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The role and effect of suture materials in small vascular anastomoses were investigated using new monofilament synthetic absorbable suture PDS. The autografts were implanted in the abdominal aortas of 30 adult mongrel dogs using PDS and polypropylene (PP) sutures, as a control.
Because of monofilament suture, PDS may not tear graft and artery, initial tissue reaction was minimal. Microscopicaly, hyalinoid degenerations were observed in the anastomotic sites using PP, but not in the PDS sites. PDS have very smooth intima at the late phase. Tensil strength decreased more slowly than that of polyglycolic acid (PGA) suture. Until now we used this material in 9 anastomoses clinically There were no complications. The authers concluded, PDS is the most adventageous suture material in anastomosing small vessel at present.

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We developed complianced suture material available for small caliber arteries. We clarified its superiority as suture material to other suture materials by means of stress-strain curve patterns and light microscopic findings. Its stress-strain curve pattern was the same as that of natural arteries. This material displayed much less relaxation than polypropylene. In tolerance test of repeated loading, this material showed almost no deformation. In light micro scopy almost no invasion of histiocytes around this suture material was observed both two weeks and two months after anastomosis. Almost no fibrosis was identified around this suture material two weeks after anastomosis, and slight but less fibrosis than around polypropylene was identified two months after anastomosis.

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Mechanism of intimal hyperplasia developing at the end-to-side anastomosis in small caliber vascular grafting was invesitigated from the view point of hemodynamics using different kind of vascular materials. In the experiment, 22 Biografts®, 3 EPTFE and 5 Dacron grafts were implanted in the fashion of aorto-iliac bypass in 30 dogs in which the terminal aorta was ligated. Development of significant intimal hyperplasia at the toe of_distal end-to-side anastomosis was observed only in the model in which blood flow to the proximal outflow segment exceeds flow to the distal outflow segment. Therefore, hemodynamics at the anastomotic sites seems to be important factor causing anastomotic intimal hyperplasia.

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In order to improve the late results of the composite graft, we performed a experimental study to investigate the intimal hyperplasia of the composing site of the Biograft. In the group without wrapping the composing site, at 6 month after implantation, We observed that the fibrin mass on the suture line is organized by the cells that infiltrated along the suture and through the juncture of the grafts. At 12 month later, the intimal hyperplasia becomes clear and its etiology is considered to fibroblasts by the EVG stain. On the other hand, in the group with wrapping the composing site using Silicon tube, the inner surface of the graft is covered with thin fiblin layer and the intimal hyperplasia is not recognized at 12 month after implantation. We conclude that at the composing site of the graft, it is possible that fibrine layer on the anastomotic line is organized by the fibroblasts and thus developes the intimal hyperplasia, so that the wrapping of the composing site is usefull for preventing the intimal hyperplasia.

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For evaluating whether 2 types of E-PTFE graft can be utilized for venous reconstruction or not, the E-PTFE graftswere implanted between innominate vein and right atrium of dog. Overall patency rate was 62%. More than half of the graft showed mild to moderate intimal hyperplasia at the anastomotic sites and the early stage of thrombosis in the center. Mesenchymal cell infiltration was recognized in 12 graft and endothelialization in 46%. Subsequently, these E-PTFE grafts were available prosthesis for venous reconstruction.

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In the animal experiment, high patency rate (96.2%) was obtained in the replacement of the iliac vein or inferior vena cava combined with a distal arteriovenous fistula using several different kinds, of synthetic vascular graft. Among several materials, the pseudointima of the removed patent grafts were compaired macroscopically and microscopically with scanning electron microscope, and that of the high-porosity knitted Dacron was the most smooth and beautiful. The endothelium-like cells proliferation was also recognized on the middle part of the Dacron but the others.

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We are attempted to more sigmplifications (1) Prefabricated-ringed-composite graft involved (a) mechanical heart valve (SJM valve), (b) large Cooley low porosity woven Dacron graft, (c) USCI ringed graft, (d) small Cooley low porosity woven Dacron graft for coronary artery. (2) Fibrin glue-oxycellulose fixation for graft preclotting. These method attempted for 10 cases with AAE, AR. Operative mortality was 1 case (10%). These method were usefullness for save intraoperative bleeding and aortic-cross clamp time.

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No matter how highly evaluated is the Gore Tex graft as arterial substitute of relatisely small caliber, there are few reports on aortic replacement with this graft. Between nine patients, who underwent aortic replacement with this grafts during the past three years and fifty-six patients, who had the same procedure with the woven dacron grafts by the same surgeon of abdominal aortic aneurysms during the past eight years, operation hours, aortic clamping hours, operative blood-loss and the patency rate of the inferior mesenteric arteries (IMA), which had been anastomored to the grafts, were compared. There resulted in not-significant difference in operation hours, clamping hours and operative blood-loss. In seven patients, who had IMA anastomoged to the Gore Tex graft, all seven IMA proved patent on the post-operative angiography. In twelve patients, who had graft-anastomosed IMA and underwent the postoperatire angiography among the dacron group, there were only three patent IMA, and there resulted in the significantly poor patency rate of IMA in the dacron group. Consequently, Gore Tex graft is demonstrated as useful aortic substitute for abdominal aortic aneurysm and aortic obstruction, in which reconstruction of some abdominal branches from the graft are neccessary

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Autologous SVG has been the standard material for arterial reconstruction in the lower extremity. In 1981, we began to use Goretex graft for F-P bypass.
Eight arterial reconstruction were performed with Goretex graft and were observed for 12 to 46 months (average 25 months). Patency rate were 100%. All patients except 2 (one was died of myocardial infarction and the other patient still has intermittent claudication in spite of the increased peripheral blood pressure) have become free from the symptom such as intermittent claudication, rest pain, skin ulcer and necrosis. These results justify the evaluation of Goretex graft as an arterial prosthesis.

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Gore-Tex grafts were used for the patients of ASO (68 cases), TAO (3 cases), abdominal aortic aneurysm (6 cases), thoracic aortic aneurysm (2 cases), aortitis (1 case) and infected aneurysm (1 case), during January 1979 and October 1985. Early obstruction of bypass graft was encountered in 2 cases of ASO and 2 cases of TAO. Late obstruction occured in 3 cases of ASO and 1 case of TAO. Thrombectomy of the obstructed bypass graft was performed successfully in 4/5 cases of ASO, and in all cases grafts are ketp patent. Patency couldn't be obtained in all three obstructed cases of TAO. In seven cases of ASO, the anatomical and extraanatomical bypass grafts were proved to be patent for more than four years.

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We implanted prosthetic grafts to 94 patients with abdominal aneurysm, and 27 patients, with abdominal aortic occlusion for the past of 15 years. Extra—anatomical bypass were applied for 22 patients with abdominal aortic occlusion, and 33 patients with iliac or iliofemoral occlusion. Anatomical bypass using prosthetic graft was perfomed in 22 patients with peripheral arterial occlusion of lower extremities. The occlusion of graft occurred in ninety percent of the patients with extra anatomical bypass. Among those cases, woven dacron and knitted velour dacron were used in 7 cases and 8 cases, respectively. There were graft infection, 4 cases; anastomotic aortic aneurysm, 5 cases; pseudoarterial aneurysm, 1 case; and edematous change around the tissue of prosthetic grafts, 1 case. The pathological findings of grafts with complications were studied. In the cases with woven dacron, ‘pseudointima’ was seen as fibrin associated with hyalinization and there were neovascuralizations or giant cell inf iltrations. In the cases with peripheral occlusion of knitted double velour dacron, neovascuralization was strikingly seen. In the case with Nakao's tetrone graft for 11 years, few neovascuralizations were seen, while atheroma formation was observed. In the case with Gore—tex, thin ‘pseudointima’ was seen and there were no cellular components in the graft

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80 artificial vascular prosthesis in revascularization surgery were discussed. All of 24 woven dacron grafts, implanted as Y-graft were patent, and also 12 woven dacron grafts, as femoro-femoral graft, were patent. One of 24 EPTFE grafts, as femoro-popliteal graft, was occluded. There was small problem in Human Umbilical Cord Vein, because of its wall thickness.

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We have already reported that centrifugal method was useful to reduce blood PFC level, and that PFC removal efficiency in centrifugal method (REPEC) was high when PFC concentration of blood (CPFC) was higher than 20g/dl, and that REPFC was low when large amount of PFC remained in retrieved plasma. This time, the REPFC of IBM-2997 cell separator was studied in 5 dogs which was administered 20.4±3.39/kg B. W. of PFC during cardiopulmonary bypass, and the feasibility of membrane plasma separator in incresing CPFC of blood or removing residual PFC in plasma. The CPFC of these dogs reduced to 22% of CPFF of control group. The feasibility of plasma separator was seemed to be expectant.

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In this study, the effectiveness of oxygenated cardioplegic solutions (Perfluorochemicals) were investigated by isolated working rat heart. Experimental time course is showed in Fig 2, And experimental groups were divided into four groups according to the contents of cardioplegic solutions. Each groups were shown in Table 2. The best recovery of aortic flow was obtained in F1-St. T group, however, it was the worst in F1 group. Rapid cardiac arrest was induced by injection of cardioplegic solution in F1-St. T group and St. T group, however, it was not seen in F1-group. It is concluded that Perfluorochemicals (FDA-20%) is useful as cardioplegic solution, but it is necessary to add some drugs for getting rapid cardiac arrest

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Fluosol-DA cardioplegia was compared with crystalloid cardioplegia and blood cardioplegia as a method of myocardial preservation during ischemic arrest. Experimental dogs were divided into three groups according to perfusates. One group received a standard crystalloid cardioplegic solution (group C), the second received a blood cardioplegia (group B) and the third received an oxygenated Fluosol cardiopleic solution (group F). MSAP, CI, SVI, LVSWI and LV max dp/dt were measured before and after cardioplegic arrest. The results documented best MSAP, SVI, LVSWI and LV function-curves showed best performance in the group F.

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Myocardial ischemia is one of the limiting factors in PTCA (percutaneus transluminal coronary angioplasty). Because, when the balloon is inflated, there will be no oxygen supply distal to the balloon. And it may cause myocardial damages. Therefore, we have an idea that we can infuse oxygenated artificial blood “Fluosol-DA (FDA)” distal to the balloon so as to relieve myocardial ischemia. And we made fundamental experiments of left coronary artery perfusion using FDA in dogs. The perfusion rate was 30ml per min., and the perfusion continued for 30min. The results were as follows: 1) FDA can be oxygenated. 2) During perfusion, cardiac function was excellent. 3) HistoLogically, there were no myocardial damages after perfusion.

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We have developed two types of bioartificial mucosa, which serves as a mucosa substitute in experimental animals. Type 1 artificial mucosa was coposed with collagen gell, fibroblast and epithelial cells, which were derived from rabbit oral cavity. Type 2 artificial mucosa was composed of a sheet of mucosal epithelial cells overlying a collagen sponge. Both artificial mucosas were transplanted to the host animal and taken successfully. Seven days after grafting, blood vessels invaded the artificial mucosa. These experimental findings revealed that the bioartificial mucosa could be used as the new method for reconstruction of oral mucosa.

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Non-implantable peritoneo-venous (i-n P-V) shunt was investigated to improve the defects of implantable P-V shunt. Two catheters with Dacron mesh were placed in abdominal cavity and superior vena cava respectively and connected to the flush bulb with one way valve outside the body. Ascites was able to be drawn from either connection of the catheters, and was concentrated to reinfuse. P-V shunt must be removed operatively before because of malfunction caused by following reasons: 1) Catheter placed in abdominal cavity is obstructed by fibrin 2) One way valve is obstructed by small debris of fibrin 3) Catheter placed in superior vena cava is obstructed by thrombi. But these causes in n-i P-V shunt were able to be improved non-operatively. The n-i P-V shunt was used in 3 patients with cirrhosis and renal failure for several months. Ascites in these patients was controled without infection.

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Thermopervaporation, which permeates only solvent in the form of a vapor through a hydrophobic membrane using vapor pressure difference as a driving force between two fluids flowing on either side, is a promising technology in the industrial field. Solute-free water can be removed from bovine plasma and blood by the thermopervaporation with a teflon membrane, demonstrating that the stable flux is obtainable oer a 4-hour interval. The porous membranes tested reject over 99% of Na⁺, K⁺ and Cl^-.

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Continuous gastric cooling (CGC) with dialysate was done in nine hemodialysis patients complicated by upper massing GI bleeding. As double lumen NG tube was used in the eight patients, four patients with duodenal bleeding (DB) had complete hemostasis and only one patient manifested recurrence. But only two out of the four patients with gastric bleeding (GB) had complete hemostasis and all patients revealed recurrence. Reinsertion of NG tube was necessary for these three patients due to the obstruction of the catheters by clot. These data indicate that CGC is more effective for the DB than GB. As it seems to to be not good to remove the clot around the bleeding point in GB, we investigated a 3 lumen, single balloon catheter (3L-SBC). This catheter makes it possible to cool and oppress the bleeding point of the stomach without removing the clot. CGC with 3L-SBC was used and very effective for the GB in one case.

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Anticancer agent is desired to be administration as selectively as possible in a high concentration to the tumor-bearing organ in order to present clinical effectiveness and removed as quickly as possible from circulating peripheral blood in order to minimize the untoward effects. Ten patients who were treated with hemoperfusion over charcoal followed by intra-arterial infusion of the high-dose anticancer agent (MMC 1.0mg/kg or ADM 2.0mg/kg) via an implantable vascular access device under radiofrequency regional hyperthermia are evaluated in this study. Nine of them had metastatic liver tumor and another one had pelvic tumor infiltrated from prostatic cancer. Remarkable reduction in a tumor size were observed in 8 patients (80%), and tumor markers decreased, in 7 out of 8 patients (87.5%). Untoward effects were minimized in this new methods. There was no lethal side effect in this treatment in spite of tremendous dosage of anticancer agents. Results in this study show that this combined therapy for advanced cancer patients deserves for further evaluation.

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A skin button made of sintered hydroxyapatite (base:12mm in diameter, column:8mm in height, nipple:5mm in diameter) was implanted in 41 year old male forearm. Neighter infection nor exudation has been observed more than 5 months until now. It has been tightly adhered to the skin around the column. The skin button carrying person has no restriction about taking bath or swimming even not taking any care of the button. This material will be very useful as a skin interface for implanted artificial organs.

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